(i) Field of the Invention
The present invention relates to a stamp and a process for preparing the stamp. More specifically, it relates to a stamp comprising a sponge material having open cells which can be repeatedly used for stamping without replenishing the ink with which the sponge material has been permeated, and an improvement of a process for preparing the stamp.
(ii) Description of the Related Art
In order to save the labor of applying a stamp ink onto the surface of a stamp every time stamping is done, the stamp beforehand permeated with the stamp ink has been used in which a sponge rubber having open cells is employed as a stamp material. Japanese Patent Application Laid-open No. (Sho) 60-193686 discloses a process for preparing a stamp which comprises depressing, thrusting and hardening the whole surface of a sponge in a concave state, except a portion for imprint formation, by a heating type extrusion process, so that the convex portion of the sponge becomes the portion which is the ink absorbing portion and can be used for the imprint formation. Furthermore, Japanese Patent Application Laid-open No. (Sho) 50-155323 discloses a method for manufacturing a stamp by pressing a porous material against a heating plate. However, this method requires a mold as the heating plate and the labor of sculpturing or etching characters, symbols and figures on the mold.
In addition, Japanese Patent Application Laid-open Nos. (Sho) 57-136652 and 49-7003 disclose a method for manufacturing a stamp which comprises coating the surface of a sponge material with a photopolymerizable liquid resin, irradiating the resin with ultraviolet rays through a positive film put thereon to bring about a photopolymerization reaction, and then washing the resin to remove the unreacted resin, thereby exposing the surface of the sponge material under the removed portion. Moreover, in Japanese Utility Model Laid-open No. (Sho) 52-71710, there is disclosed a plate stamp obtained by a similar method using a negative film. However, these methods inconveniently have intricate steps such as the formation of the negative or the positive film, coating of the resin, the photopolymerization and water washing. Furthermore, in Japanese Patent Application Laid-open No. (Hei) 3-96383, there is a description of melting the surface of a sponge directly by a thermal head, but its detailed disclosure is not present anywhere.
As described above, the conventional method for manufacturing the stamp having the open cells takes a good deal of labor and has intricate steps, and a method using a thermal head is not described in detail. Thus, a process for preparing a stamp capable of providing a sharp imprint has been desired.
On the other hand, a label word processor for making labels (hereinafter referred to as "the label word processor") can easily make labels. The label word processor is equipped with a keyboard for input and a display section comprising a liquid crystal display and the like; an internal font is printed in accordance with a command input from the keyboard or data input from the outside with the aid of the heat from the thermal head.
As shown in FIG. 9 attached hereto, a label tape cartridge 41 which can be used in this label word processor comprises a label tape 43 wound around a core 42, a feed core 44, a thermally transferrable ink ribbon 46 wound around a winding core 45, and a pressing member 47 received in a cassette case 48. Furthermore, as shown in FIG. 10, the label tape 43 comprises a tape base 43a, an adhesive layer 43b applied on its back, and a protective tape layer 43c laminated thereon. Another type of label word processor is also present in which a thermosensitive layer is formed directly on the tape base and printing is made by the utilization of a thermal head.
According to this label word processor, characters or the like are input from the keyboard, and a print content is confirmed on a display such as a liquid crystal display and the thermally transferrable ink layer 49 is transferred to the tape base 43a by the thermal head (not shown) to obtain the label tape. The ink ribbon 46 is melted and pulled out while the characters or the like are transferred to the label tape 43, thereby forming a label tape having a suitable length, the thus formed label tape being cut by a cutter (not shown). When the protective tape layer 43c is peeled, the cut label can be stuck on an object.
In the label word processor for making such a label tape, the length of the tape can usually be automatically set on the basis of a tape width and the input data, and a character size and a space between the characters can be automatically set in compliance with the set tape length. Thus, a label tape having a good finish can be easily manufactured.
However, in the case of the label manufacture by such a label word processor, the label tape itself is thick, which is obstructive, and the appearance of the print with the label on a paper is poor. In addition, since the label tape is usually made of a PET film, it is inconveniently difficult to write on the label tape with writing implements.